20391696 has 80 divisors (see below), whose sum is σ = 63051520. Its totient is φ = 6272640.

The previous prime is 20391677. The next prime is 20391713. The reversal of 20391696 is 69619302.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 20391696.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3801 + ... + 7431.

It is an arithmetic number, because the mean of its divisors is an integer number (788144).

Almost surely, 2^20391696 is an apocalyptic number.

20391696 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20391696, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31525760).

20391696 is an abundant number, since it is smaller than the sum of its proper divisors (42659824).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20391696 is a wasteful number, since it uses less digits than its factorization.

20391696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3661 (or 3649 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 36.

The square root of 20391696 is about 4515.7165544352. The cubic root of 20391696 is about 273.2023617359.

The spelling of 20391696 in words is "twenty million, three hundred ninety-one thousand, six hundred ninety-six".